1. Technical Field
The present disclosure relates to a semiconductor memory device, and more particularly, relates to an operating method of a controller for controlling a nonvolatile memory device and a mapping pattern selecting method for selecting a mapping pattern mapping a polar coded code word onto multi-bit data of the nonvolatile memory device.
2. Discussion of Related Art
A semiconductor memory device is a memory device which is fabricated using semiconductors such as silicon (Si), germanium (Ge), gallium arsenide (GaAs), indium phosphide (InP), and the like. Semiconductor memory devices are classified into volatile memory devices and nonvolatile memory devices.
The volatile memory devices may lose stored contents at power-off. The volatile memory devices include various random access memory (RAM) devices, such as a static random access memory (SRAM), a dynamic RAM (DRAM), a synchronous DRAM (SDRAM), and the like. The nonvolatile memory devices may retain stored contents even at power-off. The nonvolatile memory devices include a read only memory (ROM), a programmable ROM (PROM), an electrically programmable ROM (EPROM), an electrically erasable and programmable ROM (EEPROM), a flash memory device, a phase-change RAM (PRAM), a magnetic RAM (MRAM), a resistive RAM (RRAM), a ferroelectric RAM (FRAM), and the like. The flash memory device is roughly divided into a NOR type and a NAND type.
Polar encoding has recently been introduced as a low-complexity coding scheme for a large class of channels. Polar encoding typically represents bits by using two levels of polarity or amplitude: positive and negative. A common type is polar encoding is Non Return to Zero (NRZ). With NRZ the level of signal is determined by the binary digit being sent. Binary 1's are indicated by positive voltages and binary 0's by negative voltages. However, a need exists for a method and apparatus configured to control nonvolatile memory devices using polar encoding.